The r-modes of rotating fluids

An analysis of the toroidal modes of a rotating fluid, by means of the differential equations of motion is not readily tractable. A matrix representation of the equations in a suitable basis, however, simplifies the problem considerably and reveals many of its intricacies.Comment: 12 pages, 4 fiures, revised version to appear in A&

The g-modes of white dwarfs

The neutral g-modes of a degenerate fluid at zero temperature are analyzed. The g-modes of a degenerate fluid at finite but small temperatures are then expanded in terms of those of the zero temperature fluid. For nonrelativistic degenerate fluids it is found that (1) the g-eigenvalues are proportional to T mu(6)sub e mu(-1)sub i, where T is the internal temperature of the fluid, mu sub e and mu sub i are the mean molecular weights of electrons and ions, respectively; (2) the ion pressure is solely responsible for driving the g-modes. For white dwarfs of about a solar mass, the periods of the g-oscillations are in the range of a few hundredths of seconds

Gravitational waves and lensing of the metric theory proposed by Sobouti

We investigate in detail two physical properties of the metric f(R) theory developed by Sobouti (2007). We first look for the possibility of producing gravitational waves that travel at the speed of light. We then check the possibility of producing extra bending in the lenses produced by the theory. We do this by using standard weak field approximations to the gravitational field equations that appear in Sobouti's theory. We show in this article that the metric theory of gravitation proposed by Sobouti (2007) predicts the existence of gravitational waves travelling at the speed of light in vacuum. In fact, this is proved in general terms for all metric theories of gravity which can be expressed as powers of Ricci's scalar. We also show that an extra additional lensing as compared to the one predicted by standard general relativity is produced. These two points are generally considered to be of crucial importance in the development of relativistic theories of gravity that could provide an alternative description to the dark matter paradigm.Comment: 10 pages, 2 figures. Added a comment on the recent article by Saffari (arXiv:0704.3345v1) and small typos as well as general comments in the introuduction and conclusio

Educational case: Pseudomonas and acinetobacter sepsis due to thermal injury

Background: Multi drug resistant (MDR) Pseudomonas and Acinetobacter species are defined as resistant to at least three classes of antibiotics. Most studies have demonstrated that MDR gram negative infections convey increased mortality and morbidity. Case: An 11-year âold girl was admitted to pediatric burns unit with burn injury of approximately 68 total body surface area (TBSA). Discussion: Role of systemic antibiotics is adjunctive and never replaces surgical debridement, use of topical agents, nutritional support, increasing in immune system function and grafting. Evidence in the published literature suggests that combination therapy with Meropenem and Colistin are effective for burned patients with MDR gram negative sepsis. © 2013, Kowsar Corp

Prevalence of beta lactamase producing species of pseudomonas and acinetobacter in pediatric burn patients Prevalence de pseudomonas et acinetobacter secreteurs de blse et metallo-beta lactamases chez les brules pediatriques

Burn wound infection is a major cause of morbidity and mortality in burn victims. Pseudomonas and Acinetobacter species are among the most common organisms complicating burn wounds. Presence of extended spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) genes plays an important role in spreading β-lactam resistant strains of these organisms and is a serious condition in the treatment of the affected patients. As a result, we aimed to determine the prevalence of SHV, TEM, PER and VIM β-lactamases in Pseudomonas and Acinetobacter species isolates from burn wound swabs of children with burn injury. In this descriptive observational study, 107 Pseudomonas and Acinetobacter isolates collected from burn patients were subjected to PCR assay. Using PCR method and DNA sequencing, the existence of SHV-, TEM-, PER- and VIM-type β-lactamase encoding genes were determined. Out of the 107 Pseudomonas and Acinetobacter isolates, 66 (77.6) were ESBL positive, 26.2 were positive for SHV gene, 37.4 were positive for TEM gene, 14 were positive for PER gene and 15.9 of them harbored VIM gene. More than half of the Pseudomonas and Acinetobacter strains in our pediatric burn unit harbor β-lactamase encoding genes that make them resistant to a wide range of β-lactam antibiotics. Consequently, it is suggested to choose an appropriate antibiotic regimen based on the antibiogram pattern of the strains. © 2015, Mediterranean Club for Burns and Fire Disasters. All rights reserved